Circuit board



FIG. 1 is a perspective view of a circuit board showing my new design;

FIG. 2 is a top view thereof;

FIG. 3 is a bottom view thereof;

FIG. 4 is a left side elevational view thereof;

FIG. 5 is a right side elevational view thereof;

FIG. 6 is a front elevational view thereof; and,

FIG. 7 is a rear elevational view thereof.

The even dashed, broken lines in FIGS. 1-7 show unclaimed environment and form no part of the claimed design. 

CLAIM The ornamental design for a circuit board, as shown and described. 